If we choose to live near convergent plate boundaries, we can build buildings that can resist earthquakes, and we can evacuate areas around volcanoes when they threaten to erupt. Yes, convergent boundaries are dangerous places to live, but with preparation and watchfulness, the danger can be lessened somewhat.
Nitrification, as stated above, is formally a two-step process; in the first step ammonia is oxidized to nitrite, and in the second step nitrite is oxidized to nitrate. Different microbes are responsible for each step in the marine environment.
The dependence of the reaction rate on temperature was found to be lower than expected for nitrification in fixed-film biofilters by Zhu and Chen (2002). In particular, the effect of temperature on the reaction rate was found to be even weaker under oxygen-limiting conditions compared with ammonia-limiting conditions.